code: def update(self, other):
      n1 = self._n
      n2 = other._n
      n = n1 + n2
      if n == 0:
          # Avoid divide by zero, which creates nans
          return
      delta = self._M - other._M
      delta2 = delta * delta
      M = (n1 * self._M + n2 * other._M) / n
      S = self._S + other._S + delta2 * n1 * n2 / n
      self._n = n
      self._M = M
      self._S = S
  
imports: import numpy
label_desc: Use image node_id 4 for calling the RunningStat obj's underlying member method code with example usage: obj.update(other) without return types